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miércoles, 13 de mayo de 2015

On 11 May 2015 José Luís Anguita observed and photographed what seemed a milk & coffee Pied Flycatcher Ficedula hypoleuca within a Seville, Andalusia, urban park. He took three photos (attached) and he described the sighting as follows:

' I saw yesterday this flycatcher in a Seville park. I gave it as a female Pied and I did not pay attention to its flight as I was concentrated in taking the pictures... but once I saw them it seems atypical. We don't know if its a leucistic or another species. Its eye is not dark and it's very pale'

Once checked the photos it seems that the bird is pale indeed and that the colour is not bleached-related (feathers seem to be new, not worn). Therefore it is presumably an aberration-related subject.

According to van Grouw (2006) Dutch Birding 28: 79-89, the bird could be a 'Brown' aberration:

'Brown as aberration is defined as a qualitative reduction of eumelanin. In this mutation, the amount of pigment remains unchanged but the appearance of the eumelanin is changed (cf Kopf 1986). As a result of an inherited incomplete oxidation of eumelanin, black feathers will turn dark brown. The phaeomelanin is unaffected'.

Contrast between paler mantle and brown feathering indicating 'pale female' could support this hypothesis since :

'In nature, ‘brown’ males are very rare because they can only be born from a ‘brown’ mother and a normal father that is heterozygotous for this mutation (and of course from parents that are both ‘brown’). The chance for this to occur in nature is normally very minute.'

This is the first flycatcher of this kind known to the author.Reference:

lunes, 19 de enero de 2015

On 13.1.2015 an odd redstart was seen at Laguna de Fuentedepiedra, Málaga (Andy Paterson). It was initially thought to be a bird from an Oriental race of the Black Redstart (Phoenicurus ochruros), which show some reddish vent and underparts as in the photographed bird.

Despite the wing structure was not visible in any of the three photos, there was a clear white wing pannel and a wide and long white patch in the vent and middle of the breast, pointing towards an hybrid ochruros x phoenicurus rather than an oriental race of ochruros.

Find enclosed three photos from Andy Paterson of this, in any case, interesting and beautiful bird.

Ferran López, observer of the bird and manager of the blog quoted (see above in catalan): 'The bird shows characters of both species: rectangular head and the tuft with chocolate tones, brown tones in the breast, white undertail and rear coverts, dirty chocolate flanks etc...

Despite no telescope was available, a video and a few record shots were obtained using hand-held binoscoping technique from the cal Tet hide window and are included below. Most of the characters outlined above can be clearly noted.

Regarding the latter, this crossing is reported in Eurasia for both ♂ and ♀ amd the hybrids are said to be fairly common, accounting for a 5% of all waterfowl hybrids reported for Western Central Europe (Randler in McCarthy op.cit.). However, these authors refer that most of the reported hybrids are males (such as these birds -also including two presumed females - from the UK).

domingo, 31 de agosto de 2014

On 31 August 2014 Toni Alcocer found an odd Calidris minuta within Tancat de la Ratlla Nature Reserve, at Silla, Albufera de Valencia Natural Park. He was able to take four photos of what apparently recalls an adult Little Stint (Calidris minuta). Another obsever, Gonzalo, shared the moment.

The bird however does not look as a typical minuta, and shows some subtle structural differences and plumage features such as overall colour, breast, flanks and undertail coverts spots. Interestingly, the bird was ringed.

Any kind of plumage aberration would be discarded once there are characters, as the forementioned spots, that instead of fade or vanish, appear in this individual. And the case of a mistery stint featured in Dutch Birding back in 1996 (see the 18_1 issue of Dutch Birding with the Lars Jonsson paper here) and considered as an hybrid temminckii x minuta came to mind.

McCarthy (2006) Handbook of Avian Hybrids of the World lists quite a few Calidris cases of hybridisation but none presumably of a minuta x sp combination that might match this individual.

Is this an aberrant individual? Is this an unknown hybrid? Or what is this Calidris?

This post is aimed to collect any proposal, comment or simply to state the observed individual and the amount of variation these waders can show.

608 Audouin's Gull Larus audouinii nests. That was the 2014 count which marked a local record for the
species in its 'new' breeding site at El Molí island of Llobregat river
mouth. colonised by the species in 2009. Ringing of the colony was scheduled for June Friday 13. And the
friday 13 reputation seemed to work again: almost no activity in the
colony showed that something had went wrong.

The colony
had a great number of abandoned nests, some broken as 'crashed by something coming from
the sky', some predated but probably 'after-death' according to the
official Vet and Mammal expert that visited the colony. There were a few abandoned nests with
very young dead chicks at least two weeks before the visit, according to the
condition of the corpses .

Failure was not complete, since 21 chicks could be found and were subsequently ringed with white PVC rings coded as follows:

The joint team of Llobregat delta Consortium, Wildlife Service of the
Generalitat de Catalunya and Rangers of the Generalitat stated that a
set of five-days in a row of heavy showers, including hail, and low temperatures
coinciding exactly with hatching period of the species in late May 2014 is after the
colony fate. This had happened years before in the Ebre Delta, with a total
failure of the world largest colony, and has happened here for the 1st
time ever.

Meteo.cat radar showing the storms of 26.5.2014

Meteo.cat radar showing the storms of 31.5.2014

Regardless the disgraceful situation, this fact demonstrates how conservation dependant these colonial species are. And how, despite seeming to be leaving its former endangered status, there is still much to do for the benefit of colonial threatened seabirds such as the Audouin's Gull. Let's see what happens next year. Let's hope it will be better for the species in this important stronghold the Llobregat delta is.

This blog is

Contribucions diverses sobre l'ornitofauna de Catalunya i Espanya i sobre la conservació de la natura. Also about my view of birding in Spain, these blogs want to complete the set of data exposed in the family of Rare Birds in Spain website, blogs and also the email yahoogroup, in Spanish. They will include posts in English, Spanish and Catalan. Managed by Ricard Gutiérrez.